Constellations of the Month
by Rick Raasch
Containing the brightest star visible on earth, the constellation of Canis Major is one of the few constellations in the heavens which resembles what it is supposed to be: a large dog. Puppis, on the other hand, boasts no bright stars, and is difficult at best for even seasoned observers to identify. Stellar beacons notwithstanding, both of these constellations are rich in open clusters, as they lie along the winter Milky Way. Several interesting planetary nebulae and double stars are also found in this region. Soon galaxies will be overwhelming the skies, so if you want to find objects a bit closer and brighter, it's time to come out of the warm and do some cold weather astronomy!
M-41 Large and splashy, this fine open cluster is easily seen as a hazy patch to the naked eye, and is fully half a degree in diameter in the telescope. About 60-70 stars can be seen at low power, in many curving chains. The cluster is dominated by a bright orange star near its center. A great open cluster.
NGC 2354 Relatively large, this open cluster is about 15-20' in diameter, round, and composed of relatively bright stars and a sprinkling of fainter stars. The center seems empty, with very few stars.
NGC 2359 The Duck Head Nebula. This is a large and faint diffuse nebula which is best seen at low powers. It is about 10' in extent, and is composed of an arching segment intersected at almost right angles by a straighter component, resembling a duck's head and bill. I found it best seen with an Orion Ultrablock filter, while the Lumicon UHC filter did not do as well. This is a good object for you light bucket owners.
NGC 2362 A small but very pretty open cluster surrounding the star Tau CMa. It is about 6' in diameter, compact, and well concentrated. I counted about 40 stars with most of them being moderate in brightness. This is one of my personal favorites.
NGC 2360 This is a large open cluster, 12-15' in diameter, with about 75 stars well concentrated to the center. It is visible in the viewfinder and impressive through the telescope.
ADS 5951 One of my favorite double stars, this is a fine pair composed of yellow-orange and blue stars. It reminds me of a fainter version of the more famous Albireo. It's easily split, so check it out!
M-46 This is a bright open cluster almost a half of a degree in diameter, containing about 100 moderately concentrated stars. As a special treat, the planetary nebula NGC 2438 lies seemingly imbedded in its northeastern edge. The planetary is about 40" in diameter, grayish, and is distinctly ring-shaped. This is a great deep sky double!
M-47 About the same size as M-46, this is another fine telescopic sight. This open cluster contains about 50 relatively bright stars moderately concentrated to the center.
M-93 Another fine open cluster. It is about 20' in diameter with a distinct triangular or wedge shape. Composed of about 50 stars, it is fairly well concentrated, with a moderate range in magnitudes of the stars.
NGC 2440 This planetary nebula appears as an out of focus star, about 20" in diameter, with a bright center fading to the edges. No central star was seen in this blue-green nebula.
March: Ursa Major
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